Most people who identify as Catholic in developed countries today don’t believe in any of those (demonic possession and exorcism would be particularly fringe, but in surveys in many countries the majority identifying as Catholic don’t believe in hell or sometimes transubstantiation either)
There certainly are plenty of cultural Catholics who don't believe much of if anything that the Church teaches. The example of possession is particularly interesting though, because it's so overt. Unlike transubstantiation, where we have to take it on faith, there are documented cases of demonic possession that really defy natural explanation. Things like knowing secrets, speaking unknown languages, levitation, feats of strength, and so on have all been observed. Here[1] is one example and you can find many more, including from non-Catholic or even non-Christian specialists who have been retained to rule out mental illness and other natural explanations. Unfortunately it is a rather sensationalized subject, so there is a lot of garbage out there too.
True, but Catholicism isn't a democracy. Catholic beliefs aren't determined by what self-professed Catholics say they believe in, but what the Catholic Church itself professes.
I mean, that's one way to look at it. But in practice Catholics aren't, and never have been, a monolith, belief-wise, unless you define it so narrowly that the only Catholics are, well, maybe some of the cardinals.
(Or not even those, if you take the view of some post-Vatican-II breakaway sects who consider the Pope to be illegitimate)
That's true, there is a great deal of theological diversity within the Catholic Church, and to an extent that diversity is actually encouraged. But the Church also sets bounds on what beliefs can acceptably be called "Catholic" and those bounds are Catholic dogma. (And over the centuries theologians have actually constructed quite a baroque hierarchy of degrees of theological certainty attached to various beliefs. [1])
The actual dogmas are fairly narrow. They include things like the doctrine of transubstantiation, Jesus being both God and man, Mary being conceived without original sin. But a lot of other things aren't dogmatic. For example, it's perfectly acceptable to argue that Roman Catholic priests should be permitted to be married or that Limbo doesn't exist.
